105
T064 (Circuit A Saturated Temperature Transducer Failure)
T065 (Circuit B Saturated Temperature Transducer Failure)
Alert codes 064 and 065 are for circuits A and B respectively.
These alerts occur when the unit is configured for pressure
transducers (Configuration
UNIT
DP.XR) and the cor-
responding saturated condensing temperature is outside the
range –40.0 to 150.0°F. A circuit cannot run when this alert is
active. Use the scrolling marquee to reset the alert. The cause
of the alert is usually a faulty transducer, faulty 5v power sup-
ply, or a loose connection. Although the software supports this
option, it is not possible at the time of the writing of this speci-
fication to order the optional discharge pressure transducers.
T072 (Evaporator Discharge Reset Sensor Failure)
If the unit is configured to use the remote EDT 4 to 20 mA reset
input (Configuration
EDT.R
RES.S) and the sensor read-
ing is less than 2 mA then the alert will occur. When this occurs
the control will default to the internal setpoints. The sensor is
connected to the optional CEM module. For this sensor to be
used, the EDT 4 to 20 mA reset input (Configuration
EDT.R
RES.S) must be set to “enabled.”
T073 (Outside Air Temperature Thermistor Failure)
This alert occurs when the outside air temperature sensor
(Temperatures
AIR.T
OAT) is outside the range –40 to
240°F (–40 to 116°C). Failure of this thermistor (Temperatures
AIR.T
OAT) will disable any elements of the control
which requires its use. Economizer control beyond the vent po-
sition and the calculation of mixed-air temperature for the
sumZ algorithm will not be possible. This alert resets automat-
ically. The cause of the alert is usually a faulty thermistor, a
shorted or open thermistor caused by a wiring error, or a loose
connection.
T074 (Space Temperature Thermistor Failure)
This alert occurs when the space temperature sensor (Tem pera-
tures
AIR.T
SPT) is outside the range –40 to 240°F (–40 to
116°C). This alert will only occur if the unit is configured to use a
space temperature sensor. Configuration is done through the Unit
Control Type (Configuration
UNIT
C.TYP) configuration.
Failure of this thermistor (Temperatures
AIR.T
SPT) will
disable any elements of the control which requires its use. If the
unit is configured for SPT 2 stage or SPT multi-stage operation
and the sensor fails, no cooling or heating mode may be chosen.
This alert resets automatically. The cause of the alert is usually a
faulty thermistor in the T55, T56, or T58 device, a shorted or open
thermistor caused by a wiring error, or a loose connection.
T075 (Return Air Thermistor Failure)
This alert occurs when the return air temperature sensor (Tem-
peratures
AIR.T
RAT) is outside the range –40 to 240°F
(–40 to 116°C). The RAT is standard on all units and is located
in the return section near the auxiliary control box. This alert
resets automatically. The cause of the alert is usually a faulty
thermistor, a shorted or open thermistor caused by a wiring er-
ror, or a loose connection.
Failure of this thermistor (Temperatures
AIR.T
RAT)
will disable any elements of the control which requires its use.
Elements of failure include:
• the calculation of mixed air temperature for sumZ control
• the selection of a mode for VAV units
• economizer differential enthalpy or dry bulb control
• return air temperature supply air reset
T076 (Outside Air Relative Humidity Sensor Failure)
This alert occurs when the outside air humidity sensor (Inputs
REL.H
OA.RH) has a reading less than 2 mA. Failure of
this sensor will disable any elements of the control which re-
quires its use including economizer outdoor and differential
enthalpy control. The OA.RH sensor is located in the econo-
mizer hood and is used for control of the economizer. The sen-
sor is a loop powered 4 to 20 mA sensor. This alert resets auto-
matically. The cause of the alert is usually a faulty sensor, a
shorted or open sensor caused by a wiring error, or a loose con-
nection. The unit must be configured to use the sensor through
the Outside Air RH Sensor (Configuration
ECON
ORH.S) setting.
T078 (Return Air Relative Humidity Sensor Failure)
This alert occurs when the return air humidity sensor (Inputs
REL.H
RA.RH) has a reading less than 2 mA. Failure of this
sensor (Inputs
REL.H
RA.RH) will disable any elements
of the control which requires its use including economizer differ-
ential enthalpy control, humidification, and dehumidification.
The RA.RH sensor is located in the return air section near the
auxiliary control box. The sensor is a loop powered 4 to 20 mA
sensor. This alert resets automatically. The cause of the alert is
usually a faulty sensor, a shorted or open sensor caused by a
wiring error, or a loose connection. The unit must be config-
ured to use the sensor through the Outside Air RH Sensor
(Configuration
UNIT
SENS
RRH.S) setting.
T082 (Space Temperature Offset Sensor Failure)
If the unit is configured to use a space temperature sensor and is
using a T56 sensor with an offset potentiometer, then the alert will
occur if the potentiometer is outside the allowable range. The con-
trol will default to the software applicable setpoint because there is
no offset available that may be applied to space temperature. The
alert will automatically clear. The unit must be configured for one
of the SPT control options through the Unit Control Type (Config-
uration
UNIT
C.TYP) configuration.
T090 (Circuit A Discharge Pressure Transducer Failure)
T091 (Circuit B Discharge Pressure Transducer Failure)
Alert codes 090, and 091 are for circuits A and B respectively.
These alerts occur when the unit is configured for pressure
transducers (Configuration
UNIT
DP.XR) and the pres-
sure is outside the range 0.0 to 667.0 psig. A circuit cannot run
when this alert is active. Use the scrolling marquee to reset the
alert. The cause of the alert is usually a faulty transducer, faulty
5v power supply, or a loose connection. Although the software
supports this option, it is not possible at the time of the writing
of this specification to order the optional discharge pressure
transducers.
T092 (Circuit A Suction Pressure Transducer Failure)
T093 (Circuit B Suction Pressure Transducer Failure)
Alert codes 092, and 093 are for circuits A and B respectively.
These alerts occur when the pressure is outside the following
ranges: 0.5 to 134.5 psig when SP.XR=0, 0.0 to 420.0 psig
when SP.XR=1. A circuit cannot run when this alert is active.
Use the scrolling marquee to reset the alert. The cause of the
alert is usually a faulty transducer, faulty 5 v power supply, or a
loose connection.
T110 (Circuit A Loss of Charge)
T111 (Circuit B Loss of Charge)
Alert codes 110, and 111 are for circuits A, and B respectively.
These alerts occur when the compressor is OFF and the suction
pressure is less than 18 psig and the OAT is above –5°F for
1 continuous minute. The alert will automatically clear when
the suction pressure transducer reading is valid and greater
than 54 psig. The cause of the alert is usually low refrigerant
pressure or a faulty suction pressure transducer.
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